The present invention relates to preparing fresh food products such as fish or produce for shipment from the site of harvesting to market, and more particularly, to a method and apparatus for providing easily movable and quickly erectable portable large capacity bins for bulk storage and dispensing of ice or other similar materials.
It is important that the grower and the fisherman be able to quickly cool their product at the site of harvesting, namely, at the dock or in the field. Otherwise, poor quality food may be delivered to the consumer due to inability of the grower or fisherman to quickly cool his product to reduce pathological decay rates. Produce and seafood require large volumes of ice for cooling, but this requirement is seasonal. Because fixed ice plants are expensive, it is not practical to operate them for only two months out of the year. Hence, the growth of the agricultural and seafood business has been hindered because the grower or fisherman has been unable to quickly cool his product at the production site.
The trend in recent times is to provide portable icing systems which may be rapidly and safely moved from site to site to provide icing services thereby allowing for near annual use of the system and greatly reducing the cost when compared to under-utilized fixed ice plants. Currently, portable ice generators and portable ice application equipment are available and are used extensively. Ice storage, however, has largely been a problem in portable icing systems due to the large volumetric, structural, and cost requirements. As a result, ice has been stored by dumping it on a concrete pad, either in an exterior or interior location and manually shoveling it or using earth moving equipment, removing the ice from the pile and depositing it into conveyor means for transport to the ice application equipment. This method results in health, safety, and sanitation problems as well as wasted energy and water due to the high melt rate of uninsulated storage areas.
With the growing inability of electric utilities to meet peak demand loads, the storage component of a typical ice system takes on more importance by providing the ability to generate ice during "off-peak" periods and to utilize the inventory of ice from the storage during "on-peak" periods. This form of thermal energy storage can reduce on-peak electrical load to near 90%.
The automatic and sanitary handling of fragmentary ice in an ice storage bin has historically presented an exceedingly difficult problem. Fragmentary ice stored in a storage bin tends to fuse together and become difficult to move. As a result, fragmentary ice in bulk storage is difficult to handle because it is virtually incapable of flowing out of the bin by gravity. The inability of bulk fragmentary ice to flow by gravity has been recognized and the prior art has employed a device known as an ice rake to facilitate the handling of bulk ice. An ice rake is a type of drag conveyor which contacts the top of a pile of ice and is maintained in contact therewith by cables and weights.
Typically, ice rakes are positioned horizontally on an ice mass within the ice storage bin and serve to remove the fragmentary ice from the top of the pile to a discharge conveyor. Such systems have the disadvantage that they require considerable overhead clearance for the pulleys, cables, and motors required to maintain the ice rake in a horizontal position and to control the movement of the ice rake. In addition, such devices typically require a cumbersome counterweight movement mechanism in order to raise the ice rake to refill the bin with a new supply of fragmentary ice.
Various bin unloading systems have been proposed for materials other than fragmentary ice; however, many of them are inappropriate for use in the sanitary environment required for the storage and handling of ice. In particular, many of the conveying devices used for other materials have motors and gears located within the storage bin, which could lead to the introduction of grease or other impurities into the ice bin. Bin unloading systems such as these are therefore inappropriate for use in bulk ice storage bins.
Rakes often are raised and lowered by timing devices, and misjudgment of ice flow or ascent of rake frame can bury frames in ice. Thus, there is a need for a suitable mechanism for use in ice storage bins in order to provide efficient, sanitary unloading of fragmentary ice that has fused together. The present invention is directed toward filling that need.